... Nitriding process,Bimetallic layer of this single screw and barrel. Specifications of this single screw and barrel:diameter: Φ15mm~ Φ250mmlength: ... ~0.7mm, surface roughness:Ra0.4, screw straightness:0.015mm, Chromium plated hardness:>900HV ... single-screw types can be made.Scope of application:PP, PE, PS, EVA, ABS, PVC, APC, PMMA pelletizing, foaming,sheet and plate extruder etc. single screw and barrel ...